Nicholas,
I´m afraid it is far worse then you think. There is an enourmous amount of money to be made in their area. Not from tourist money but in terms of gold and wood exploration.
In Portuguese the words for explore and exploit are the same word. It is difficult in talking to a Brazilian to determine exactly what they are talking about in such discussions. The concept of going into a new area to determine what is there and map etc is very difficult to separate in their minds from going into a new area and simply stripping it of anything useful.
One starategy Brazil has used is to give huge jungle reservations to indian tribes. In many places the indians themselves have sold logging and mining rights, against the law, to illegal operators who then bribe public officials to be able to take the wealth out of the area and get it into the legal system.
There´s just too much money to be made in such areas and the only thing that keeps these places wild is there inherent inaccessability. Without rivers or roads to move timber you can't even log illegally. This tribe will remain in isolation until that happens. Once it does their way of life is doomed.
Typically a tribe will abandon the old ways as soon as a new technology comes along, we all carry a Bic for survival too, right? Back in our own history the fire piston was getting set to be THE way to light fire and then the sulphur match was invented and the rest, as they say, is history.
When the portuguese started to exploit the Brasil wood for dye back in the 1500´s they would gather a group of natives and chop down a few trees with an iron axe. The Indians would react as you would to see a light saber. Then the sales pitch would come. "We´ll be back in a few weeks and if you have a a pile of Pau Brasil here on the beach we will give you one of these (the axe)" They would all labor away with their old methods and make a pile of wood only to be better equipped to chop more once the traders came back.
First contact is a very complicated issue and if anyone has a good solution for it you could probably run for office in Acre State. Mac